<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      let sum = 0
      let arr = [1, 3, 4, 5, 7, 54]
      for (let i = 0; i <= arr.length - 1; i++) {
        console.log(arr[i])
        sum = sum + arr[i]
      }
      alert(`该数组平均值为 ${sum / arr.length}  `)
    </script>
  </body>
</html>
